Childhood adversity (e.g., abuse, neglect, or household dysfunction), is a common experience significantly contributing to the leading causes of death and increased US economic health burdens. Childhood adversity causes long-term alterations on the nervous, endocrine, and immune systems well into adulthood, including dampening of the neuropeptide oxytocin (OXT). A healthy OXT system facilitates responsive social engagement and promotes maternal-infant (M-I) synchrony (reciprocal gaze, affect speech, and touch). Optimal M-I synchrony fuels early brain development and prevents low empathy, disruptive behavior, poor social adaptation, cognitive deficits, and psychopathology in children. We posit that mothers with childhood adversity will have more difficulty with M-I synchrony, due in part to a dampened OXT system, and will benefit from interventions that improve responsive, nurturing, engagement by epigenetic regulation of the OXT system. Most interventions are costly, complex, and time-consuming. We aim to fill this gap by testing whether a simple early behavioral intervention (ATVV) will improve OXT system function and M-I synchrony in mothers with childhood adversity. The ATVV (Auditory, Tactile, Visual, Vestibular) is a 15-minute behavioral intervention consisting of infant- directed speech, moderate touch massage, eye to eye gaze, and horizontal rocking. We extend the known success of ATVV with preterm infants to full-term infants. We will compare M-I synchrony at 3 postnatal months in 250 first-time mothers (and their full-term infants) randomized to apply ATVV daily from birth to 3 months (n = 125) or receive infant care education in an attention control group (n = 125). We apply a rigorous measure of M-I synchrony that micro-codes video-recorded M-I behavior quantifying shared gaze, affect, speech, and touch. Coding requires only 3-minutes of interaction and is valid when infants can reliably interact starting by 3 months of age. We will also assess ATVV's effect on maternal and infant peripheral OXT level, a known biomarker of M-I synchrony. OXT levels relate to quality of M-I synchrony, yet we extend this knowledge to identify an epigenetic role of the oxytocin receptor gene (OXTR). We will analyze maternal plasma for OXTR methylation, OXTR gene expression, OXTR protein, and oxytocin peptide in late pregnancy, and at 1, 2, and 3 postnatal months (along with infant saliva OXT). In summary, aims are to 1) determine effects of daily ATVV, compared with an attention control group, from birth to 3 postnatal months on behavioral and physiologic measures of M-I synchrony in mothers with childhood adversity, and 2) for the first time identify molecular mechanisms in the OXT system underlying M-I synchrony in maternal plasma. Regression based methods (including covariates) will assess ATVV effects on M-I synchrony and OXT measures, and identify relations among M-I synchrony and oxytocin measures. Clustering methods will be used to discover molecular profiles. An early behavioral intervention that successfully promotes M-I synchrony in vulnerable women through epigenetic regulation of the OXT system can then be tested in a multi-site clinical implementation trial with other high-risk groups.